摘要:
Treatment of ((1,2,5-eta)-4-methyl-5-oxapentadienyl)Ir(PMe(3))(3) (1) with HBF4 . OEt(2) leads to protonation at carbon C3 and production of [((1,2,5-eta)-4-methyl-5-oxapenta-1,4-diene)Ir(PMe(3))(3)](BF4-)-B-+ (4) At room temperature, this species rearranges to the iridafuran complex [fac-CH3C - CH - C(CH3)- O - Ir(PMe(3))(3)(H)](BF4-)-B-+ (5). Similar treatment of the five-membered iridacycle, mer-CH2=CCH=C(CH3)OIr(PMe(3))(3)(H) (3) with HBF4 . OEt(2) results in direct electrophilic attack at carbon Gland production of the mer isomer of 5, [mer-CH3C - CH - C(CH3)- O - Ir(PMe(3))(3)(H)](BF4-)-B-+ (6) In the tris(PEt(3)) reaction system, treat ment of the six-membered ring compound, mer-CH=CHCH=C(CH3)OIr(PEt(3))(3)(H) (7), With HBF4 . OEt(2) leads to protonation at C3 and production of [mer-CH=CHCH2C(CH3)=OIr(PEt(3))(3)(H)](BF4-)-B-+ (9). Upon heating in tetrahydrofuran at reflux, this species rearranges to the iridafuran complex, [mer-CH3C - CH - C(CH3)- O - Ir(PEt(3))(3)(H)](BF4-)-B-+ (10). Protonation of the five-membered-ring compound, mer-CH2=CCH=C(CH3)OIr(PEt(3))(3)(H) (8), With HBF4 . OEt(2) also produces iridafuran 10 via direct electrophilic addition to C1. Excess I-2 reacts with compound 10 exclusively at the metal center to produce the neutral diiodide compound, trans-CH3C - CH - C(CH3)- O - Ir(PEt(3))(2)(I)(2) (11), while excess Br-2 reacts with 10 at both the iridium center and C3 of the ring to form the electrophilic aromatic substitution product, trans-CH3C - C(Br)- C(CH3)- O - Ir(PEt(3))(2)(BT)(2) (12). Molecular structures of [mer-CH3C - CH - C(CH3)- O - Ir(PEt(3))(3)(H)](PF6-)-P-+ (the PF6- salt of 10), trans-CH3C - CH - C(CH3)- O - Ir(PEt(3))(2)(I)(2) (11), and trans-CH3C - C(Br)- C(CH3)- O - Ir(PEt(3))(2)(Br)(2) (12) have been determined by single-crystal X-ray diffraction studies.